1. Field of the Invention
This invention relates generally to stents adapted for use in providing structural support for the walls of body conduits.
2. Discussion of the Prior Art
Stents have been widely used in the body to provide structural support for the walls of body conduits. For example, stents have been used in the field of urology to provide structural support for the urethra, particularly in proximity to the prostate. Vascular stents have been particularly adapted for use in both veins and arteries to add support to weakened vascular walls, for example, in proximity to aneurysms. In each of these cases, the stent provides a tubular structure with sufficient hoop strength to support the walls while maintaining patency of the conduit.
Stents of the past have typically been provided in the form of a tube having a low-profile state facilitating insertion, and characteristics for being expanded to a high-profile state to provide structural support and lumen patency. Stents have been formed from various plastics, as well as a variety of metals and alloys. In some cases, stents have been formed as a tubular mesh that facilitates movement between the low-profile and high-profile states. Such a stent is disclosed and claimed in applicant's U.S. patent application Ser. No. 09/303,113, filed on Apr. 30, 1999, and entitled "Improved Ureteral Stent System Apparatus and Method," which is incorporated herein by reference.
In order for the tubular stents to be formed of solid materials and also be expandable, the walls of the stents have needed to be cut, sometimes in intricate patterns, in order to facilitate expansion. Particularly in the case of metal stents, these small intricate patterns have been cut by lasers in an expensive and time-consuming fabrication process.
In accordance with one surgical operation, such a stent has been mounted over the balloon of a catheter and inserted in the low-profile state into the femoral artery. Then the catheter is advanced until the stent is moved into the desired location. At this point, the balloon as been inflated within the stent, moving its walls outwardly to the high-profile state. Then the balloon is deflated and the catheter withdrawn, leaving the stent to structurally support the body conduit.
The metal stents have been particularly desirable for their high hoop strength. Unfortunately, to provide such stents with the expansion characteristics desired, an intricate fabrication process is required. This, of course, adds to the expense associated with this type of stent.